Based on our estimates, more than 40 developers are actively marketing villas and condominiums off-plan on Koh Samui in 2026. Roughly 15% of those entities have not completed a single project. For any buyer committing a deposit of 30-50% of the purchase price before receiving keys, verifying the developer is not a formality - it is the primary mechanism for protecting capital.
Our team has monitored the Koh Samui market for years, and we observe a recurring pattern: each year, two or three new firms emerge with polished renderings, aggressive payment schedules, and no track record of delivered units. Meanwhile, experienced developers with five to ten completed projects in districts such as Bophut, Maenam, and Lamai offer comparable pricing alongside a measurable delivery history. The methodology below sets out the full due diligence framework our analysts apply to developers on Koh Samui and Phuket.
Quick answer
- We verify a minimum of 5 parameters before recommending any developer: track record, financing structure, permits, build quality, and contractual protections
- Warning threshold: a delay exceeding 6 months on a prior project, or a demand for more than 50% of the purchase price before foundations are complete
- As of 2026, our estimates indicate only around 25 developers on Koh Samui have at least 3 completed and handed-over projects
- No bank financing for the construction means the developer builds entirely from buyer deposits, which raises the risk of work stoppages
- There are no escrow accounts for foreign property buyers in Thailand - this protection mechanism does not exist in the Thai legal framework
- Practical buyer protection rests on: a payment schedule tied to construction milestones, contractual penalty clauses, and the developer's financial health
Options and scenarios
Step 1: Track record - how many projects and with what delays
The first check our analysts run is the number of completed projects. On Koh Samui, a developer with a minimum of 3 delivered projects over the past seven years has a documented history. We compare actual key-handover dates against the dates promised in sales materials. A delay of up to 3 months is treated as a market norm in Thai conditions, given that the monsoon season (October through December) regularly halts construction. A delay of 6-12 months is a warning signal. A delay exceeding 12 months removes the developer from our shortlists entirely.
In practice, our analysts visit previous projects on the ground. We speak with building managers and owners, asking specifically about delivery punctuality, finish quality, and how the developer responded to post-warranty defects.
Step 2: Construction financing structure
This is a critical point that buyers frequently overlook. We ask the developer directly: is the construction co-financed by a bank loan, or does it rely entirely on buyer deposits? Based on our estimates, approximately 60% of villa projects on Koh Samui in 2026 are funded exclusively from buyer payments. That model is not inherently problematic, but it requires the developer to maintain a consistent sales pace. If sales slow, construction can stall.
Developers holding a credit facility with a Thai bank - such as Bangkok Bank or Kasikornbank - have already passed that institution's credit assessment, which functions as an additional quality filter. We request written confirmation of any bank financing.
Step 3: Completeness of permits
We examine three documents:
- Building permit (ใบอนุญาตก่อสร้าง) - we verify the permit number, issue date, and alignment with the current project design
- Environmental Impact Assessment (EIA) - required on Koh Samui for projects exceeding 80 residential units or buildings above 10,000 sqm of floor area (as of 2026)
- Chanote title deed - we verify at the local Land Office that the plot carries no mortgage exceeding the project's value
The absence of a building permit at the point of sale is an absolute red flag. On Phuket we observe similar requirements, though EIA thresholds vary by district - Kamala and Surin, for example, carry additional development density restrictions.
Step 4: Build quality - verified on the ground
Our analysts inspect the developer's earlier projects and assess their condition two to five years after handover. We examine: roof construction quality (critical in a tropical climate), drainage system performance, window and door joinery condition, and the state of the pool and shared areas. On Koh Samui, high humidity and salt air accelerate corrosion, so material quality has a direct and measurable effect on long-term maintenance costs.
Step 5: Payment schedule and contractual safeguards
Because no escrow mechanism protects foreign buyers in Thailand, the payment schedule is the primary tool of buyer protection. Based on our practice, an acceptable payment structure looks as follows:
- Reservation: 50,000 - 100,000 THB
- Contract signing: 20-30% of purchase price
- Foundation completion: 20-25%
- Structural completion: 20-25%
- Key handover: 20-30%
A developer requesting more than 50% of the price before foundations are poured is effectively funding current operating costs from future buyers' money. We also scrutinize contract clauses covering delay penalties (market standard: 0.01-0.05% of contract value per day) and the conditions for refunding payments if the project is not completed.
Step 6: Legal review of the purchase contract
Every developer contract is forwarded to an independent Thai-licensed lawyer for analysis. We check: the language of the agreement (both English and Thai versions must exist; in a Thai court the Thai version is binding), precision of the property description, title transfer provisions, clauses covering latent defects, and warranty terms (market standard: 1-2 years of structural warranty).
Step 7: Company financials and registered capital
Financial data for companies registered with Thailand's Department of Business Development (DBD) is publicly available. We review registered capital, three years of financial results, and shareholder structure. A developer with registered capital below 5 million THB executing a project worth 200 million THB raises serious questions in our analysis about the capacity to complete if sales momentum drops.
Comparison table
| Parameter | Lower-risk developer | Medium-risk developer | Higher-risk developer |
|---|---|---|---|
| Completed projects | 5 or more | 2-4 | 0-1 |
| Delays on prior projects | Up to 3 months | 3-6 months | More than 6 months |
| Bank financing | Confirmed in writing | Partial or undisclosed | None - buyer deposits only |
| Payment before foundations | Up to 30% of price | 30-50% of price | More than 50% of price |
| Building permit | Issued before sales launch | In process | Not obtained |
| Registered company capital | Above 20 million THB | 5-20 million THB | Below 5 million THB |
| Delay penalties in contract | Yes, 0.03-0.05% per day | Yes, below 0.01% per day | Absent or nominal |
| Structural warranty | 2 years or more | 1 year | No clause present |
Risks and mistakes
Risk 1: Buying from a developer with no delivery history. On Koh Samui between 2020 and 2024, at least 4 projects totalling more than 60 units were suspended mid-construction due to developer financial problems. Buyers recovered an average of 20-40% of funds paid after multi-year litigation.
Risk 2: Relying on guaranteed rental return promises. A developer promising 8-10% annual returns in districts such as Chaweng or Lamai should be able to document those figures on existing completed projects. Based on our data, the realistic net rental yield from short-term villa rentals on Koh Samui in 2025 was 5-7% per year before tax.
Risk 3: Ignoring the Thai version of the contract. In the event of litigation before a Thai court, the Thai-language version of the document is binding. The English translation may omit or soften key provisions.
Risk 4: Failing to verify the land title type. On Koh Samui, our analysts encounter plots carrying a Nor Sor 3 Gor title instead of a full Chanote. The former offers weaker legal protection and is harder to sell or transfer.
Risk 5: Paying a reservation deposit without a written agreement. Some developers accept reservation payments on verbal terms alone. Without a written reservation contract, recovering that deposit is, in practice, extremely difficult.
FAQ
How do we check a Koh Samui developer before paying a deposit?
We start with the DBD database to verify registration details, registered capital, and financial results. We then visit the developer's prior projects on site, cross-check permits at the local authority office, and instruct an independent Thai-licensed lawyer to review the contract. The full process typically takes two to four weeks.
Are there escrow accounts for foreign buyers on Koh Samui?
No. Thailand does not have escrow accounts for foreign property buyers in the sense familiar from European or North American markets. Buyer protection relies on a payment schedule tied to construction milestones, contractual delay penalties, and the developer's underlying financial strength.
What construction delay is acceptable in Thailand?
Our analysts treat a delay of up to 3 months as within market norms, largely because the monsoon season interrupts work on a predictable annual cycle. A delay of 3-6 months is a warning signal requiring explanation from the developer. Delays exceeding 6 months are treated as a serious problem in our risk assessments.
How much registered capital should a Koh Samui developer have?
For a project valued above 100 million THB, we consider registered capital of at least 10-20 million THB a minimum indicator of financial resilience. Lower registered capital signals that the company is entirely dependent on buyer payments and holds no financial buffer.
What permits should a developer hold before launching sales?
The minimum requirement is a valid building permit and a confirmed land title - ideally a Chanote. For larger projects on Koh Samui, an approved EIA report is also required. Launching sales without a building permit in place is an absolute red flag in our framework.
What does a safe payment schedule look like for a Koh Samui villa?
A secure structure links each payment to a verified construction milestone: 20-30% at contract signing, 20-25% after foundation completion, 20-25% after structural completion, and 20-30% at key handover. Any demand exceeding 50% of the price before foundations are poured is a clear warning signal.
Does a Koh Samui developer need bank financing?
Bank financing is not a legal requirement, but its presence indicates that the developer has passed an institutional credit assessment - an independent quality filter. Per our estimates, approximately 60% of villa projects on Koh Samui in 2026 rely solely on buyer deposits.
What happens if a Koh Samui developer fails to complete the project?
The buyer can pursue repayment through the Thai court system. Proceedings typically last two to four years. Recoverable amounts depend entirely on the developer company's financial position and average 20-40% of the sum paid. Preventive due diligence is, by any measure, less costly than litigation.
Researching property in Phuket or Koh Samui? Get in touch - our analysts will prepare a data brief for your shortlisted location.